Jan 29 (Reuters) - U.S. judges in at least five states blocked federal authorities from enforcing President Donald Trump's executive order restricting immigration from seven Muslim-majority countries.

However, lawyers representing people covered by the order said some authorities were unwilling on Sunday to follow the judges' rulings.

Judges in California, Massachusetts, Virginia and Washington state, each home to international airports, issued their rulings after a similar order was issued on Saturday night by U.S. District Judge Ann Donnelly in New York's Brooklyn borough.

Donnelly had ruled in a lawsuit by two men from Iraq being held at John F. Kennedy International Airport.

While none of the rulings struck down Friday's executive order by the new Republican president, the growing number of them could complicate the administration's effort to enforce it.

The rulings add to questions about the constitutionality of the order, said Andrew Pincus, a Mayer Brown partner representing two Yemeni men who were denied U.S. entry from an overseas flight despite being legal permanent residents.

"People have gone through processes to obtain legal permanent resident status, or visas," Pincus said. "There are serious questions about whether those rights, which were created by statute, can be unilaterally taken away without process."

Trump's order halted travel by people with passports from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days, and stopped the resettlement of refugees for 120 days.

He said these actions were needed "to protect the American people from terrorist attacks by foreign nationals admitted to the United States."

The order sparked a global backlash, including from U.S. allies that view the actions as discriminatory and divisive.

Attorneys general from California, New York, 13 other states and Washington, D.C., meanwhile, in a statement condemned and pledged to fight what they called Trump's "dangerous" and "unconstitutional" order.

The U.S. Department of Homeland Security on Sunday said it "will comply with judicial orders," while enforcing Trump's order in a manner that ensures those entering the United States "do not pose a threat to our country or the American people."

SAFE, NOT SORRY

Striking that balance has caused confusion, according to lawyers who worked overnight and on Sunday to help travelers at JFK Airport, Washington Dulles International Airport in northern Virginia, and elsewhere.

Immigration lawyer Sharifa Abbasi said some Border Patrol agents at Dulles refused to let lawyers talk with detainees, even after being shown an order from U.S. District Judge Leonie Brinkema requiring such access.

Abbasi said the agents instead told the lawyers to call their agency's office, where no one was answering.

"There is really no method to this madness," Becca Heller, director of the New York-based International Refugee Assistance Project organization, told reporters on a conference call.

Supporters of Trump's order said authorities acted properly in swiftly taking steps to enforce it.

"It is better (to) be safe than sorry," said Jessica Vaughan, director of policy studies at the conservative Center for Immigration Studies in Washington.

Lawsuits on behalf of more than 100 individual travelers have been filed nationwide, activists and lawyers estimated.

Some have come from large corporate firms including Mayer Brown, Kirkland & Ellis, and Cleary Gottlieb Steen & Hamilton.

CURBS ON TRUMP'S ORDER

In Boston, U.S. District Judge Allison Burroughs on Sunday temporarily blocked the removal of two Iranians who have taught at the University of Massachusetts, and had been detained at the city's Logan International Airport.

Burroughs' ruling appeared to go further than Donnelly's by barring the detention, as well as the removal, of approved refugees, visa holders and permanent U.S. residents entering from the seven countries. Donnelly's order forbade only removal.

Matthew Segal, legal director of the American Civil Liberties Union of Massachusetts, in a statement called Burroughs' ruling "a huge victory for justice" in the face of what he called Trump's "unconstitutional ban on Muslims."

The U.S. Constitution's First Amendment guarantees the free exercise of religion. Trump's order sought to prioritize refugees fleeing religious persecution, which the president said was aimed at helping Christians in Syria.

Burroughs' ruling also prompted some Trump critics to urge holders of green cards, which allow foreign nationals to live and work permanently in the United States, to fly into Boston, to lessen the risk of detainment.

White House Chief of Staff Reince Priebus said several times on NBC's "Meet the Press" that Trump's order does not affect green card holders "moving forward" or "going forward."

In a ruling on Sunday, U.S. District Judge Dolly Gee in Los Angeles directed the return to the United States of Ali Khoshbakhti Vayeghan, who authorities had sent back to his native Iran following Trump's order.

The ruling from Brinkema, in Alexandria, Virginia, barred the Homeland Security agency from removing an estimated 50 to 60 legal permanent residents who had been detained at Dulles.

In Seattle, U.S. District Judge Thomas Zilly barred the government from removing two people, who were not named in court papers. He scheduled a Feb. 3 hearing on whether to lift that stay. (Reporting by Nate Raymond and Mica Rosenberg and Jonathan Stempel in New York; Additional reporting by Andrew Chung, Dan Levine and Yeganeh Torbati; Editing by Jonathan Oatis and Mary Milliken)